artículo
Connexin hemichannel composition determines the FGF-1-induced membrane permeability and free [Ca2+](i) responses
Fecha
2008Registro en:
10.1091/mbc.E07-12-1240
1939-4586
1059-1524
MEDLINE:18495870
WOS:000259160400030
Autor
Schalper, Kurt A.
Palacios Prado, Nicolas
Retamal, Mauricio A.
Shoji, Kenji F.
Martinez, Agustin D.
Saez, Juan C.
Institución
Resumen
Cell surface hemichannels (HCs) composed of different connexin (Cx) types are present in diverse cells and their possible role on FGF-1-induced cellular responses remains unknown. Here, we show that FGF-1 transiently (4-14 h, maximal at 7 h) increases the membrane permeability through HCs in HeLa cells expressing Cx43 or Cx45 under physiological extracellular Ca2+/Mg2+ concentrations. The effect does not occur in HeLa cells expressing HCs constituted of Cx26 or Cx43 with its C-terminus truncated at aa 257, or in parental nontransfected HeLa cells. The increase in membrane permeability is associated with a rise in HC levels at the cell surface and a proportional increase in HC unitary events. The response requires an early intracellular free Ca2+ concentration increase, activation of a p38 MAP kinase-dependent pathway, and a regulatory site of Cx subunit C-terminus. The FGF-1-induced rise in membrane permeability is also associated with a late increase in intracellular free Ca2+ concentration, suggesting that responsive HCs allow Ca2+ influx. The cell density of Cx26 and Cx43 HeLa transfectants cultured in serum-free medium was differentially affected by FGF-1. Thus, the FGF-1-induced cell permeabilization and derived consequences depend on the Cx composition of HCs.